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Punjab (PTB) · Chapter test · Free

9th Class Physics Chapter 4 TestTurning Effects of Forces

30 marks · 40 minutes · 21 questions. Covers: CHAP 4: Turning Effects of Forces.

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9th Class Physics Chapter 4 Test

9th Class · Physics · Punjab (PTB)

Name: ____________Roll No: ________Class/Section: ________Date: ________Total marks: 30Time: 40 minutes

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

  1. A spanner 25 cm long is used to open a nut. If a force of 400 N is applied at the end of a spanner what is the torque acting on the nut:

    1. 98 Nm

    2. 100 Nm

    3. 150 Nm

    4. 1600 Nm

  2. The mathematical form of the second condition of equilibrium is:

  3. A body is in stable equilibrium when its centre of gravity:

    1. Is at its heightest position

    2. Is situated at its bottom

    3. Is at lowest position

    4. Keeps its height if displaced

  4. Racing cars made stable by:

    1. Increasing their speed

    2. Decreasing their mass

    3. Lowering their centre of gravity

    4. Decreasing their width

  5. Value of tan 30o is:

    1. 0.5

    2. 0.866

    3. 0.577

    4. 0.707

  6. The reason that a car moving on a horizontal road get thrown out of the road while taking a turn is:

    1. The reaction of the ground

    2. Rolling friction between tyre and road

    3. Gravitational force

    4. Lack of sufficient centripetal force

  7. What is the center of gravity of round plate?

    1. Corner of the plate

    2. Center of the plate

    3. Center of axis

    4. Center of rod

  8. The gravitational pull of the earth provides:

    1. Centrifugal force

    2. Center of gravity

    3. Centripetal force

    4. Equilibrium

  9. Which of the following is special type of torque?

    1. Resolution of force

    2. Moment arm

    3. Rigid body

    4. Couple

  10. Complete the equation:Vectors

Q2. Short questions (Attempt any 6 of 8 · 6 × 2 = 12)

  1. What is resolution of force?

  2. Define momentum of a force. Prove that, where is angle between r and F.

  3. A ripe mango does not normally fall from the tree. But when the branch of the tree is shaken, the mango falls down easily. Can you tell the reason?

  4. Why now-a-days, steering wheels of smaller diameter are installed vehicles?

  5. Write the centre of gravity of square, rectangular and triange.

  6. Define Neutral Equilibrium with example.

  7. Define centripetal acceleration and write its equation.

  8. What is the significance of coupe in rotational motion?

Q3. Long questions (Attempt any 2 of 3 · 2 × 4 = 8)

  1. How the stability of an object can be improved? Give a few examples to support your answer.

  2. Explain like and unlike parallel forces with help of diagram.

  3. Explain the turning effect of a force, by an activity.